The purpose of these studies was to determine if an immunomodulator was present in caprine serum. Controlled studies demonstrated that CSF-I, material fractionated from caprine serum possessed an immunomodulatory compound. Caprine serum was further fractionated into it?s peptidic components and a small contaminant of immunoglobulin G and albumin (Caprine serum fraction - immunomodulator 2, or CSF-I2). This was refined to a three peptidic isolate collectively identified as tri-peptidic immunostimulant or TPI. CSF-I2 does not possess antibacterial capabilities (as typically characteristic of a cationic peptide or defensin), does not contain a level of endotoxin sufficient to promote a pyrogenic response, and its functional ability to improve animal survival after an infectious challenge does not reside with molecular weight components greater than 10 kilodaltons, effectively excluding the immunoglobins, albumin, cytokines, and collectins. CSF-I2 was able to significantly reduce the mortality observed in chickens (from 80% to 13%) infected with Pasteurella multocida (Willeford et al., 2000), in mice (from 83% to 13.3%) infected with Salmonella typhimurium, and in canines (from 50% to 9.8%) diagnosed with parvovirus. CSF-I2 may well prove to provide prophylactic and therapeutic health benefits to humans. CSF-I2 may effectively combat pathogenesis when used as either an adjunct with conventional therapy (e.g., antibiotics) or when provided as the primary medicant.